From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- security/integrity/iint.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 security/integrity/iint.c (limited to 'security/integrity/iint.c') diff --git a/security/integrity/iint.c b/security/integrity/iint.c new file mode 100644 index 000000000..8ec1a3436 --- /dev/null +++ b/security/integrity/iint.c @@ -0,0 +1,71 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2008 IBM Corporation + * + * Authors: + * Mimi Zohar + * + * File: integrity_iint.c + * - initialize the integrity directory in securityfs + * - load IMA and EVM keys + */ +#include +#include "integrity.h" + +struct dentry *integrity_dir; + +/* + * integrity_kernel_read - read data from the file + * + * This is a function for reading file content instead of kernel_read(). + * It does not perform locking checks to ensure it cannot be blocked. + * It does not perform security checks because it is irrelevant for IMA. + * + */ +int integrity_kernel_read(struct file *file, loff_t offset, + void *addr, unsigned long count) +{ + return __kernel_read(file, addr, count, &offset); +} + +/* + * integrity_load_keys - load integrity keys hook + * + * Hooks is called from init/main.c:kernel_init_freeable() + * when rootfs is ready + */ +void __init integrity_load_keys(void) +{ + ima_load_x509(); + + if (!IS_ENABLED(CONFIG_IMA_LOAD_X509)) + evm_load_x509(); +} + +int __init integrity_fs_init(void) +{ + if (integrity_dir) + return 0; + + integrity_dir = securityfs_create_dir("integrity", NULL); + if (IS_ERR(integrity_dir)) { + int ret = PTR_ERR(integrity_dir); + + if (ret != -ENODEV) + pr_err("Unable to create integrity sysfs dir: %d\n", + ret); + integrity_dir = NULL; + return ret; + } + + return 0; +} + +void __init integrity_fs_fini(void) +{ + if (!integrity_dir || !simple_empty(integrity_dir)) + return; + + securityfs_remove(integrity_dir); + integrity_dir = NULL; +} -- cgit v1.3.1